Gas panel

ABSTRACT

A gas panel for use with a tool for manufacturing a semiconductor includes a one-piece manifold body having an inlet for receiving a process gas. The manifold body has at least one lateral wall extending in the general direction of gas flow. The lateral wall includes at least one active device site having an active device thereon. The active device is in gas communication with a gas carrying path formed within the one-piece manifold. The active device may be a manual valve, a pneumatic valve, a pressure regulator, a pressure transducer, a purifier, a filter or a flow controller. The gas is received from the active device at a continuation of the gas flow path in the manifold body and is conveyed to a manifold outlet for ultimate to the tool.

BACKGROUND OF THE INVENTION

The invention relates in general to gas handling systems forsemiconductor processing and in particular, to gas panel systems whetherof a localized nature or distributed around a semiconductor processingtool.

Wafer fabrication facilities are commonly organized to include areas inwhich chemical vapor deposition, plasma deposition, plasma etching,sputtering and the like are carried out. In order to carry out many ofthese processes, it is necessary that the tools which are used for theprocess, be they chemical vapor deposition reactors, vacuum sputteringmachines, plasma etchers or plasma enhanced chemical vapor deposition,be supplied with various process gases which gases may be reactive orinert or provide reactive species.

For instance, in order to perform epitaxial deposition, silicontetrachloride has bubbled through it a carrier gas such as dry nitrogen,which then carries silicon tetrachloride vapor into an epitaxialdeposition chamber. In order to deposit a silicon oxide dielectriccoating, also known as a deposited oxide coating, silane (SiH₄) isflowed into the tool and oxygen is flowed into the tool where they reactto form (SiO₂) on the surface of the wafer. Plasma etching is carriedout by supplying carbon tetrachloride and sulfur hexafluoride to aplasma etcher tool. The compounds are ionized, to form reactive halogenspecies which then etch the silicon wafer. Silicon nitride may bedeposited by the reaction of dichlorosilane and ammonia in a tool. Itmay be appreciated that in each instance pure carrier gases or reactantgases must be supplied to the tool in contaminant-free, preciselymetered quantities.

In a typical wafer fabrication facility the inert and reactant gases arestored in tanks which may be located in the basement of the facility andwhich are connected via piping or conduit to a valve manifold box. Thetanks and the valve manifold box are considered to be part of thefacility level system. At the tool level an overall tool system, such asa plasma etcher or the like, includes a gas panel and the tool itself.The gas panel contained in the tool includes a plurality of gas pathshaving connected therein manual valves, pneumatic valves, pressureregulators, pressure transducers, mass flow controllers, filters,purifiers and the like. All have the purpose of delivering preciselymetered amounts of pure inert or reactant gas from the valve manifoldbox to the tool itself.

The gas panel is located in the cabinet with the tool and typicallyoccupies a relatively large amount of space, as each of the activedevices are plumbed into the gas panel, either through welding tubing tothe devices or combinations of welds and connectors such as VCRconnectors available from Cajon Corporation or the like.

Gas panels are relatively difficult to manufacture and hence expensive.In a combination VCR connector and welded tubing system the individualcomponents are held on shimmed supports to provide alignment prior toconnections at VCR fittings. Misalignment at a VCR fitting can result inleakage.

In addition, it has been found that VCR fittings often tend to comeloose in transit and some gas panel manufacturers assume that the VCRfittings have loosened during transit, possibly admitting contaminantsto the system.

Welds are relatively expensive to make in such systems but are typicallycarried out using a tungsten inert gas (TIG) system, having an orbitalwelding head to weld a tube stub and a tube together. The welding musttake place in an inert atmosphere, such as argon, and even then leads todeterioration of the surface finish within the tubes. One of theimportant characteristics of modern-day gas panel systems and gashandling systems is that the surfaces of the gas handling equipment thattend to have the gas or vapor contact them must be made as smooth andnonreactive as possible in order to reduce the number of nucleationsites and collection sites where contaminants may tend to deposit in thetube, leading to the formation of particulates or dust which wouldcontaminate the wafers being processed.

Additional problems with conventional gas panels relate to the fact thata combination VCR and welded system of the type currently used todaytypically requires a significant amount of space between each of thecomponents so that during servicing the VCR connections can be accessedand opened. In addition, in order to remove an active component from acontemporary gas panel, many of the supports of the surroundingcomponents must be loosened so that the components can be spread out toallow removal of the active component under consideration.

Most wafer fabricators are aware that it is only a matter of time until,for instance, the silane lines in the gas panels are "dusted." "Dusting"occurs when air leaks into an active silane line causing a pyrophoricreaction to take place yielding loose particulate silicon dioxide in thetube, thereby contaminating the line. Other lines also can becontaminated. For instance, those which carry chlorine gas used inetchers or which carry hydrogen chloride used in other reactions.Hydrogen chloride mixing with moisture present in the humidity of airproduces hydrochloric acid which etches the interior of the tube,roughening it and increasing the number of nucleation sites and thelikelihood that unwanted deposition would occur inside the tube. In bothof these cases, as well as in others, it would be necessary then to openthe particular line in the gas panel in order to clean it.

In addition, individual component failures may require a line beingopened in order to clean it and is time consuming and expensive.

What is needed, then, is a new type of gas panel which is compact,inexpensive to manufacture and easy to service.

SUMMARY OF THE INVENTION

In accordance with the present invention, a gas panel assembly isprovided including a plurality of active device receiving one-piece gasor vapor manifolds. The active device receiving manifolds are arrangedso that they receive gas or vapor at an inlet end, pass the gas or vaporalong to a plurality of interior channels to a plurality of activedevice receiving stations which may be connected to an active device orhave connected thereto a gas return cap and ultimately deliver the gasor vapor from an outlet for ultimate supply to a tool.

The inventive gas panel assembly is easy to manufacture, in that astandardized manifold is used with a standardized footprint forconnection to the active devices. Each of the active device sites ispositioned along the face of the substantially rectangular manifold andis oriented to extend at substantially right angles to the face of theactive device manifold and therefore out of the general flow path. Eachof the devices is connected to the manifold by a plurality of Allen-headbolts which hold the device base onto the manifold and which may bequickly and easily removed in order to remove a particular device fromthe system without disturbing other portions of the system.

The manifolding system is also self-aligning, in that each manifold is arepeatable machined component which has been prefabricated. There is nonecessity either to provide welded connections or VCR and tubeconnections directly to the active devices as the connections are madethrough and support provided by the manifold itself. By tucking withinthe manifold each of the inlet and outlet connection loops from themanifold between adjacent stations, this greatly saves space and allowsa great reduction in the amount of space over that required by a priorgas panel assembly.

The gas panel assembly embodying the present invention is easy tomanufacture in that each of the active devices is separately aligned. Ifmisalignment were to occur, for instance, between a pressure regulatorand the device receiving station on the surface of a one-piece manifold,an adjacent valve mass flow controller or the like would not bepositioned out of alignment with the general manifolding structure as aresult thereof. Thus, any misalignment which may occur has beenuncoupled from neighboring stations through the use of the manifoldingsystem. Tolerance stack-up problems are also avoided by the simultaneousability of the manifold to connect with and register the active devices.

Each of the active devices which are connected to the manifold may beprefabricated in that they include a combination seal and screw capturemechanism component, the seal including a keeper for holding the seal inalignment with the active device and the screws being held captured bynylon split rings to hold the screws within the bores of the activedevice mount. This allows for quick and easy assembly. The activedevices are seated upon edge seals at the active sites. The edge sealsdo not require extensive or fine surface preparation yet provide good,leak-free and contaminant-free joins at the gas flow inlets and outletsbetween the manifold and the active devices. The seals are easilyremovable for replacement during repair. They include keepers forself-locating which is particularly helpful when replacing an activedevice on a manifold face in the field.

The inventive gas panel manifold system also allows an entiremanifolding assembly, or stick, to have applied thereto heated tape orother types of heaters in order to heat all of the manifold boresextending among the active device components and maintain a low vaporpressure gas or vapor in a vapor state throughout each of the processgas lines of the system.

The inventive gas panel manifolding system allows the gas panel to beeasily reconfigured by a user in the field as welds and VCR connectionsneed not be broken. An active device may be replaced or added simply bylifting it out of connection with an active device site and a new oneconnected thereto.

A pair of nitrogen purge inlets is provided, both at the upstream andthe downstream end of the one-piece manifolds so that should it benecessary to remove an active device from the manifold, dry nitrogen canbe blown both backward and forward through the manifold. Dry, cleannitrogen would exit at both the exposed inlet and outlet ports theactive device site and contamination of the rest of the manifold duringthe course of the changing of the active device site be eliminated.

In addition, in a particular embodiment of the present invention themanifolded gas panel system includes pressure transducers having visualdigital readouts so that the pressure can be directly viewed by anoperator at the site as well as transmitted to a control computer.

In an additional feature of the present device, the gas panel system isenclosed within a gas panel housing having a floor, sides and a cover.Extending across the floor of the gas panel housing is a plurality ofthreaded mounts adapted to engage mounting apertures in the ends of eachof the gas panel manifolds. The mounts allow the upper surfaces of themanifold, which receive the active devices, to be individually alignedinto a single plane. This allows a rapid assembly of active devicesacross the gas panel system and allows bridging connectors to be easilyaligned with the overall gas panel active device plane defined by eachof the manifolds. The single device plane construction also provideseasy access to the Allen-head bolts holding the active devices to themanifolds.

U-tube type bridge connectors, having long connector legs and shortcross tubes connected together by Cajon elbows for interconnectingsuccessive manifolds to bridge various manifolds, provide a route forpurge gas, such as nitrogen. The long tubing provides mechanicaladvantage allowing limited flexure of the short bridging tube. TheU-tube connection is thus dimensionally forgiving for any slightmisalignment which may occur in the horizontal plane defining the activedevice surfaces. It may also be appreciated that a snug fit is notprovided between the threaded support fasteners and the active devicemanifolds to allow a slight amount of horizontal play between themanifolds for easy U-tube connection therebetween. The U-tube may alsobe formed by bending a tube into a U-shaped configuration which wouldavoid the necessity of welding.

The ability to suspend the manifolds above the surface of the gas panelenclosure allows circulation of purge and vacuum air around assemblies.Many building codes for wafer fabrication facilities require prescribedamounts of purge air to sweep leaked process gas out of the housings ofthe gas panels for safe disposal. The improved sweep provided by thesuspension of the manifolding assemblies above the floor aids in theisolation of any leaks which may occur within the gas panel system fromthe wafer fabrication operators.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a gas panel system including a housingand a gas panel mounting plate;

FIG. 2 is a perspective view of the gas panel shown in FIG. 1;

FIG. 3 is a top elevational view of the gas panel shown in FIG. 2;

FIG. 4 is a perspective view of a bottom portion of the gas panel shownin FIG. 2;

FIG. 5 is a perspective view, with portions shown in phantom, of a gasmanifold shown in FIG. 2;

FIG. 6 is an exploded perspective view, with portions shown in phantom,of an outlet gas panel manifold for an alternative embodiment;

FIG. 7 is a perspective view of an inlet gas panel manifold for analternative embodiment;

FIG. 8 is a perspective section view of a mass flow controller used withthe gas panel embodying the present invention;

FIG. 9 is a view of a bottom portion of a mass flow control base blockconnected in jumpering configuration with portions of the gas panelsystem;

FIG. 10 is an exploded perspective view of a bottom block of the massflow controller showing details of its assembly with a gas panelmanifold;

FIG. 11 is a perspective view of a deformable edge-type seal elementshown in FIG. 10;

FIG. 12 is an exploded perspective view of a keeper and C-ring seal;

FIG. 13 is a perspective view of the keeper shown in FIG. 12 engagingthe C-ring seal;

FIG. 14 is a sectional view taken between a portion of the mass flowcontroller and a portion of one of the gas panel manifold showingdetails of the engagement between the C-ring seal and the manifold;

FIG. 15 is an exploded perspective of a pneumatic control valve showingdetails of a flange mounting assembly for coupling with a gas manifold;

FIG. 16 is a perspective view of an edge-type seal used in the assemblyshown in FIG. 15;

FIG. 17 is an exploded perspective view of a jumper conduit;

FIG. 18 is a view, partially in section, and exploded, of details of aconnection fitting of the jumper conduit shown in FIG. 17;

FIG. 19 is a perspective view, partially in section, showing details ofthe mounting of a gas manifold above the gas panel support platform;

FIG. 20 is a perspective view of a partially disassembled gas panelstick to show details of some of the connection relations therein;

FIG. 21 is an exploded perspective view of a flange for coupling a valveto a gas manifold;

FIG. 22 is a section view of the flange shown in FIG. 21;

FIG. 23 is a perspective view of an alternative embodiment of anassembly gas manifold;

FIG. 24 is a top elevation, with portions in phantom, of the manifoldshown in FIG. 23;

FIG. 25 is a side elevation, with portions in phantom, of the manifoldshown in FIG. 23; and

FIG. 26 is a section of a portion of the assembled gas manifold shown inFIG. 23.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings and especially to FIG. 1, a gas panelassembly, generally identified by numeral 10, is shown therein andincludes a gas panel housing 12 having a gas panel 14 positioned betweenan upper housing half 16 and a lower housing half 18. The gas panelassembly receives multiple process gases from a source and provides themto a tool for fabricating a semiconductor wafer.

The housing is adapted to confine gases which may leak from the gaspanel 14 to the immediate vicinity of the gas panel and to carry themaway efficiency. In order to confine the gases, the gas panel itself hasextending therefrom a plurality of posts 20 which contact a top wall 24of the upper portion of the housing 16. The housing also includes a pairof end walls 26 and 28, a back wall 30 and a front wall 32. The bottomhousing 18 includes a bottom wall 34 having a plurality of inletapertures 36 formed therein adapted to receive gas flow lines coupled toother portions of the gas panel 14. The apertures 36 are sizedsignificantly larger than the diameter of the gas flow lines to alsofunction as sweep air inlets into the housing 12. Swept air is exhaustedthrough an exhaust plenum 38 which may be coupled to a suitable lowpressure or vacuum source. A plurality of electrical connections 40 isalso positioned in the bottom wall 34 to allow wiring to be connected toportions of the gas panel 14.

As may best be seen in FIG. 2, the gas panel 14 is shown therein and hasa plurality of process gas sticks or process gas assemblies 50, 52, 54,56 and 58. A nitrogen purge gas assembly 60 is also positioned on analuminum platform 62. The aluminum platform 62 has tubing inlet bores70, 72, 74, 76, and 78 as well as a purge gas bore 80 formed therein forconnection to inlets of each the gas sticks. The process gas sticks 50,52, 54, 56 and 58 are substantially identical. Each of the sticksincludes an inlet 100 as is shown in the exemplary stick 50. The inlet100 comprising a U-shaped tube having a threaded portion of a VCRfitting 102 connected thereto. The U-shaped tube 100 is coupled to atube base 104 which is coupled to an inlet manifold 118 shown. Themanifold also includes an end wall or face 120. Each of the sticksincludes a plurality of active devices or gas components.

A process gas such as silane or the like is delivered from a lineconnected to nut 102 through the U-tube 100 and into the base 104 whereit is delivered to the inlet manifold. A manual valve 130, comprisingone of the active devices or gas components and mounted on the base, maybe turned to close transmission for the process gas through themanifold. The manifold has a plurality of bores formed therein, whichbores are in communication between the inlet 100 and the valve 130. Thegas is then passed to a pneumatic valve 134 which is controllablethrough a pneumatic stem 136 from a suitable source of pneumatic gas. Apurge valve 140 is connected through a bridging U-tube 150 to a secondmanifold 152.

Elongated rectangular manifold 152, as shown in FIG. 5, includes a pairof sidewalls 160 and 162, a lateral bottom wall 164, a lateral top wall166, and end walls 168 and 170. The manifold is substantially unitaryand comprising a solid piece defining an inlet station 170 and aplurality of active device stations 172a-172d extending there along,including a mass flow controller station 174, second mass flowcontroller station 176, and an outlet station 180. It may be appreciatedthat successive stations are connected by bores drilled into the blockor manifold 152.

The bendable element 150 is connected to the inlet 170 and delivers gasto a bore 190 which is coupled to a second bore 192 providing an inlettube to first active device station 172a. The first active devicestation 172a has a pressure regulator 200 mounted on it, which receivesgas from the bore 192 and delivers gas with reduced pressure backthrough the bore 194, which is then delivered to a bore 196. The gas issupplied to second station 172b having a pressure transducer device 206positioned thereon. The pressure transducer 206 has a visual read-out207 for providing a visual indication or the pressure to a user. it alsohas an electrical signalling connection for sending a pressure signaloff panel. The flow of gas continues through a bore 208, to a bore 210and delivered to a third station 172c to which a filter/purifier 212 ismounted.

The filter/purifier removes moisture from the gas stream and deliversthe dried gas stream back through a bore 213, to a bore 214. The driedgas supplied through the bore 214 to the active device station 172 isdelivered to a pressure transducer 220 which then delivers the gas aftermeasuring the pressure to a bore 222, supplying gas to a bore 224, whichis coupled by an aperture 226 to an inlet of a mass flow controller 228.The mass flow controller 228 meters the flow of gas in accordance withelectrical signals it receives. It delivers the metered gas output to anaperture 230 which supplies the metered output of the gas to a bore,coupled to supply gas to a bore 234 providing gas at the outlet 180. Theoutlet 180 has connected to it a pneumatic valve 240 which is connectedby bridging connector through chained pneumatic valves 242, 244, 246 and248, which selectively allowed gas to flow to an outlet line 250 fordelivery off the gas panel.

In addition, purge gas, such as dry nitrogen or argon, can be receivedat the purged gas inlet 270, supplied by a U-tube 272 to a purge gasrectangular manifold 274, having laterally extending faces including amanual valve 276 positioned in communication with bores therein toenable or disable purged gas, such as nitrogen from traveling throughthe remainder of the manifold 274. A pneumatic valve 280 couples the gasto a pressure transducer 282, which then may feed the gas through eitheran elongated U-tube 284 to other portions of the purged gas manifoldingsystem 60, including an outlet manifold 286. It also may feed the gasthrough a plurality of pneumatic valves 290, 292, 294, 296 or thepneumatic valve 140, which are coupled by bridging elements to supplypurge gas to the center manifolding sections of the gas sticks 50, 52,54, 56 and 58. The pneumatic valves are controlled by a plurality ofpneumatic lines 300, which are driven from an electrical control block302, which receives electrical inputs from a suitable outside source.

The purge gas is then delivered through the U-tube into the block 286,where it passes through a pneumatic valve 310 and a pressure regulator312, and is delivered to the outlet 250. It may be appreciated that thevalves may be cycled in such a manner that purge gas may be flowed bothinto the inlet valve stack side, including valves 290 through 296 and140, and the outlet stack side, valves 240 through 248, causing purgegas to sweep inwardly from both ends of the manifold 152, keeping themanifold clean while a repair is taking place.

As may best be seen in FIG. 7 an alternative embodiment of an inletmanifold includes a first active device site 400, a second active devicesite 402, and a third active device site 404. Each of the sites 400, 402and 404 includes an outer circumferential ring respectively, 406, 408and 410 for engagement with an outer edge type connector. The U-tubeinlet is connected to an aperture 412 to feed gas through a bore 414 toa second bore 416 which delivers the gas to an inlet 420.

The gas then flows through the manual valve 130 and is delivered to anoutlet aperture 418 which supplies a gas through a bore 420 to a secondslanting bore 422, coupled with the active site 402. The bore 422 isconnected to an aperture 424 for supplying gas to the pneumatic valve134 and the gas exits the pneumatic valve 134 at an opening 430 whichsupplies gas to a bore 432 connected to a bore 434.

A second pneumatic valve may be coupled at the site 404 which pneumaticvalve is a three-way valve able to receive process gas such as silane orthe like from the bore 434 which is delivered to the valve at theaperture 440. In one state, the valve will then transfer the process gasto its outlet aperture 442, which supplies the gas to a bore 444 and abore 446 to deliver the gas to a manifold outlet 450 coupled to thejumper 150. However, in another mode, purge gas may be received at theaperture 460 and supplied by a transverse bore 462 to a vertical bore464 to the valve and thereby supply either backward through the bore 434or in most practical applications, forward through the aperture 442 forflushing of other parts of the line. In addition, since the inletmanifold block is exemplary of all manifold blocks, the transfer bore462 is used for transferring gas across blocks so that nitrogen from thenitrogen manifold 60 may be transferred across all of the inlet blocksvia the transverse bores.

An alternative embodiment of an outlet manifold 500 is shown in FIG. 6and includes an inlet bore 502 for receiving gas from a mass flowcontroller, regulated gas flow is then transferred through a slantingbore 504 to a second slanting bore 506 and delivered to an active devicesite 508 to which a valve is connected. The gas is delivered to anaperture 510 for delivery to a valve such as the valve 240 or the like.The gas is then delivered downward through a vertical bore 515 to atransverse bore 514, terminating in a first bore coupling 516 and asecond bore coupling 518. Fittings 520 and 522, respectively connectedto the bore couplings for delivery of gas transversely so that aselected gas may be supplied through the panel through the single outlet250.

As may best be seen in FIGS. 15 and 16, a typical pneumatic valve, suchas the pneumatic valve 112, includes a valve actuator 114, which iscommercially available. The valve actuator has valve components whichcommunicate through a pneumatic interface fitting 552, which is coupledby a pneumatic line to the pneumatic manifold. The valve 112 isconnected to a flange 554, having a rectangular base 556, and a valveaccepting collar 558. A plurality of manifold mounting bolts 560 extendthrough apertures 562 for connection with the gas manifold block.

The valve 112 may be preassembled with seal elements attached to itthrough the use of a prefabricated keeper 570 which is substantiallyrectangular and includes a plurality of apertures 572 through which thebolts 560 extend. The bolts 560 are trapped by nylon split rings 574which lightly engage the bolts, but hold them in the bores 562 so thatafter preassembly the bolts will not fall out and the unit can bepackaged together.

A seal ring 580, having a ring proper 582, for effecting sealingengagement between the valve and the manifold, includes a ledge 584having a plurality of semi-circular tabs 586 positioned thereabout. Thetabs 586 engage an edge or shoulder 590, which defines an aperture 592in the keeper 570. The keeper 570 receives a plurality of small bolts594 at respective apertures 596, which are in registration withapertures formed in the bottom of the rectangular base 556 of the flange554, which holds the keeper against the bottom of the flange 554. Thebolts 594 engage threaded and counterbored apertures 595 formed in theflange 554. The threaded bores 595 act as a holder or retainer forcoupling the keeper 570, and hence the seal ring 580 to the bottom 556of the flange 554 prior to assembly with the manifold block.

The sealing ring 580 extends slightly below the keeper 570 but istrapped in registration with an opening 602 in the bottom of the flangeand extends slightly below the keeper at an extension portion. At best,the unit may be completely preassembled and may be quickly added to themanifold. The flange type base is exemplary of similar flange type basesused throughout the manifolding system wherein the flange may bepreassembled with seal rings held securely by keepers.

Another example of such an arrangement is shown in FIGS. 17 through 18,wherein a typical jumper, such as the jumper 150, is shown therein. Thejumper 150 includes an inlet block 702 having a stem 704 for connectionin gas conducting contact with a tube 706. An elbow 708 is welded to thetube 706 and a second elbow 710 carries gas from the elbow 708 to across piece tube 712. A first return elbow 714 is connected to a secondreturned elbow 716 to deliver gas to an outlet tube 718 coupled at atube fitting 720 to a block 722. Each of the blocks 702 and 722 includesrespective bolts 726, 728, 730 and 732, which extend through the block.Bolt 726 is held by a plastic split ring 740 within a bore 742 of theblock. The bolt 728 is held by a split ring 744 within a bore 746 of theblock 702. A tabbed seal table ring 750 is positioned in a ring keeperaperture 752 of a metal keeper 754. The keeper 754 has a pair of keepermounting bolt apertures 756 and 758, which receive keeper mounting bolts760 and 762 to hold the keeper and to trap the seal ring 750 inregistration with the opening from the tube 704 into the keeper andultimately into the manifold. Likewise, the bolt 730 extends through abolt aperture 770. The bolt 732 extends through a bolt aperture 772 intoapertures 774 and 776 of a keeper 780. The bolts are held in lightengagement prior to assembly by snap rings 790 and 792 and keeper 780holds a seal ring 794 in engagement with the bottom of the block via thebolts 800 and 802, which extend through apertures 804 and 806 of thekeeper.

An alternative embodiment of a flange for use with a multiple port orthree-way valve such as an Aptech 3550, valves 140, 290, 292, 294 and296, may best be seen in FIGS. 21 and 22. A valve flange 820 includes aflange base 820 to having an upstanding cylindrical flange section forcontact with a valve such as a pneumatic valve or the like. A first bore826 extends between a gas connection aperture 828 and a second bore 830extends to a gas connection aperture 832. Both apertures 828 and 832terminate bottom ends of the bore. The upper end of the bore 826terminates in an aperture 836. The upper end of the bore 830 terminatesin an aperture 838. The bores 828 and 832 are at a bottom portion 832 ofthe flange bottom 822.

A pair of metal keepers 850 and 852 are substantially rectangular hold aplurality of edge type seals 854, 856 and 858. The seal 854 ispositioned at an opening 855a of a bore 855b extending to a boreaperture 855c. The seal 856 is positioned at the aperture 828 and theseal 858 is positioned at the aperture 832. The seal 854 sits in asealing receiving aperture 860 of the keeper 850. The seal 856 sits in asealing ring receiving aperture 862 of the keeper 850. Seal ring 858sits in a keeper receiving aperture 864 of keeper 852, and keeper 864also includes a spare or extra aperture 866 which may be used in otherapplications.

A plurality of keeper holding bolts 880, 882 and 884 extend throughrespective apertures 890, 892 and 894 of the keeper 852 and to contactwith the flange 822. A plurality of split rings 910, 912, 914 and 916contact the threaded fasteners including threaded fasteners 870 and 872for mounting a flange on the gas panel. In order to hold the threadedfasteners within the threaded fastener bores including the bores 874 and875, a plurality of keeper bolts 924, 926 and 928 extends throughapertures 930, 932 and 934 to secure the keeper 850 and the accompanyingseal rings 854 and 856 against the bottom of the flange 852. Thus, theentire flange assembly provides highly localized apertures forconnection to a manifold body. Each aperture has associated with it arelatively small seal ring for the prevention of leakage between therespective bores 830, 826 and 855b, and the manifold. This allows leaksto be easily detected.

An exemplary mass flow controller 228, as may best be seen in FIG. 8, isused with the gas panel. The mass flow controller includes a pair ofbody blocks 1000 and 1002, bypass 1004 is mounted in a block 1000. Gasis received is in an inlet block 1006 through a gas aperture 1008 and isdelivered through a bore 1010 to a bore 1012 within which the bypass ismounted. A portion of the gas flows through a sensor tube 1016 whichprovides an electrical signal to circuitry 1018 indicative of the rateof flow. A control signal is supplied to an electromagnetic valve 1020,which receives gas through an aperture 1022 of a block 1024, upon whichthe valve is mounted. Gas is then released through a bore 1026 to a boreaperture 1028 for delivery to other parts of the gas panel system.

A simplified version of the mass flow controller 28 with some detailremoved for clarity, as may best be seen in FIG. 9, discloses the mannerin which the mass flow controller may be connected to a manifoldingsystem having a first gas panel manifold 1030 with active site regions1032 and 1034 thereon. A manifold bore 1036 is connected to the inletblock bore 1010. The outlet bore 1026 is connected to a manifold bore1042 in a second one-piece gas panel manifold 1040.

A keeper 1050, as shown in FIGS. 10 and 11, having a seal ring 1052mounted in a keeper aperture 1054, is positioned at the aperture 1034,which is the inlet to the mass flow controller. Likewise a keeper 1060,having a seal ring 1062, positioned in a bore 1064, is mounted on themanifold 1040, and couples the outlet aperture 1028 of the control block1024 to the manifold 1040. The controller is mounted by a pair of bolts1070 and 1072 to the manifolds 1030 and 1040.

It should be appreciated that the edge seal 1050 includes a plurality ofsemi-circular tabs 1080 extending thereabout for supporting the seal inthe keeper prior to assembly.

In an alternative arrangement, as may best be seen in FIGS. 12-14, aC-ring type seal 1098 may be used between the inlet block 1010 of themass flow controller and the manifold block 1030. The C-ring seal 1098includes a substantially toroidal split ring 1100 having a helicallywound spring 1102 positioned therein for supporting the split ring 1100.A keeper 1104 holds the split ring assembly 1098 in contact with itself.The keeper 1104 includes a first arcuate section 1116 having a splitring tab 1118 formed thereon for engagement with an open slot 1120 inthe split ring. Likewise, the second wave-like arcuate section 1122 hasa tab 1124 for engaging the split ring seal 1098. A shoulder section1130, and the shoulder section 1132, also engage the opening 1120 to thesplit ring 1098. The keeper functions as the other keepers do in thesystem. It holds the split ring 1098 in registration with one of theapertures of the mass flow controller, when the mass flow controller isbeing attached to a manifold.

One of the advantages of the present invention is that the various gasmanifolds may be mounted at selected heights above the aluminumplatform. As may best be seen in FIG. 19, an inlet manifold 110 ismounted on a standoff 1200, which is identical to other standoffs 1200,extending through the platform 62. The standoff 1200 includes a boltportion 1204 which is in threaded engagement with a sleeve 1206 at abottom bore 1208. The sleeve 1206 includes an upper bore 1210 whichreceives a second or mounting bolt 1212 in threaded engagementtherewith. The mounting bolt extending through a mounting bracket 1214.

It may be appreciated that the height at which the upper wall 51 of theinlet manifold 51 may be supported may be adjusted and may be alignedwith other upper walls to provide a substantially planar, multiple wallsurface for the attachment of bridging connections between successivegas sticks. In addition, a slight amount of play is allowed between abore 1226 within which the sleeve is located and the sleeve itself, toallow for slight lateral transitions or movement of the manifolds withrespect to one another to allow easy cross connections between themanifolds.

In another embodiment of the instant invention, a gas manifold assembly1300, as may best be seen in FIG. 20, includes a VCR inlet 1302, whichreceives gas and sends gas through a jumper 1304 to a first gas manifold1306, having a laterally extending upper wall 1308, having a pluralityof active sites 1310, 1312 and 1314, positioned thereon.

For purposes of showing the geometry of the manifold, the active sitesare unpopulated. But for instance, site 1310 would likely have a manualvalve and sites 1312 and 1314 would likely have pneumatic valvesconnected to them. The position between the sites are inlet and outletbores 1324 and 1326, pair of bores 1328 and 1330, extending between site1310 and active site 1312 and the like. A cross connect 1334, whichreceives a gas, such as a purged gas or nitrogen at a bore 1336, passesa gas to a second bore 1338, and then into a bore 1340, which isconnected to the active site 1312, which is able to route gas to asecond jumper 1344, coupled to a second gas manifold 1346.

The second gas manifold 1346 includes an upper wall 1348, having aplurality of active sites 1350, 1352, 1354 and 1356 coupled by pair ofv-connected bores which are connected to a mass flow controller 1362 ofwhich only the blocks and the housing are shown. The mass flowcontroller having an inlet block 1364 connected to receive gas, a firstbody block 1366 having a bypass 1368 therein, and a valve or outletblock 1370 connected to an outlet manifold 1372. The outlet manifold1372 receives regulated gas from the mass flow controller at a bore1374, and passes the gas to an active site 1376 which includes a valveor the like.

Another manifolding system 1400 is specifically adapted to be used in amoisture sampling system for determining the levels of trace amounts ofmoisture carried in a gas or other vapor stream. In operation, gas isflowed into the inlet 1408 and is received at a port 1420 and isdelivered to a first valve station 1422, having a first pneumatic valve1424 mounted thereon.

The gas may then be supplied to a moisture scrubber station through thevalve 1424. The scrubber station 1426 has a scrubber connector 1428connected thereto with a pair or tubing stubs 1430 and 1432 forconnection to a moisture scrubber. Also connected to the inlet is apneumatic valve 1442, connected at a pneumatic valve station 1444 toreceive gas therefrom. The scrubber station 1426 is connected to a thirdvalve station 1450 having a pneumatic valve 1452 connected thereto.

The pneumatic valve 1452, like pneumatic valve 1442, is connectable tosend gas from the inlet to a mass flow controller 1460 mounted at acontroller station 1462.

In normal operation, nominally completely dry gas is supplied to themass flow controller by opening valve 1424 and valve 1452 while holdingvalve 1442 closed. This causes the inlet gas to be fed through themoisture scrubber where moisture is removed. The dry gas is then fed tothe mass flow controller.

In the event that a measurement of the amount of moisture in the gas isto be made, the valves 1424 and 1452 are closed. Valve 1442 is opened,and the gas to be measured is flowed directly into the mass flowcontroller. Downstream of the mass flow controller is a permeation site1468 having a permeation cell 1470 connected thereto for supplying atrace amount of moisture to the gas, after it flows out of the mass flowcontroller. The gas is then delivered to a first pneumatic valve 1486and a second pneumatic valve 1488 at valve sites 1490 and 1492,respectively.

A trace moisture sensor 1496 is connected to receive gas from the valve1486 and delivers the gas to a valve 1498. In addition, gas from thepermeation cell 1470 may be delivered to the valve 1488 for laterdownstream delivery to other locations. An outlet 1500 is provided fromvalve 1498 and an outlet is provided from the valve 1488.

Zero mode operation, when the scrubber is connected in series with themass flow controller, causes the valves 1486, 1488, and 1498 to beopened allowing some moisture carrying gas to enter the sensor cell 1496and other moisture carrying gas to be exhausted out through the valve1488.

In a span mode, which is necessary to determine a transfer function ofthe overall apparatus, valves 1486 and 1498 are open, causing all of thegas to flow through the sensor 1496 and out the valve V6 at a low flowrate. In a sample measuring mode valves 1486, 1488 and 1498 are allopen.

While there have been illustrated and described particular embodimentsof the present invention, it will be appreciated that numerous changesand modifications will occur to those skilled in the art, and it isintended in the appended claims to cover all those changes andmodifications which fall within the true spirit and scope of the presentinvention.

What is claimed is:
 1. A gas panel for handling plural process gases,comprising:a plurality of one-piece manifold bodies, each of saidmanifold bodies having thereon at least three identical componentreceiving stations, each of said component receiving stations having agas inlet and a gas outlet, the gas outlet from a first componentreceiving station of the plurality being connected by a permanentconnection within the manifold to a gas inlet to a neighboring componentreceiving station; a plurality of gas components, each of said gascomponents being connected to a respective receiving station on one ofthe manifold blocks, said gas components comprising at least one valveand at least one mass flow controller.
 2. A gas panel according to claim1, wherein one of said gas components comprises a purifier.
 3. A gaspanel according to claim 1, wherein one of said gas components comprisesa filter.
 4. A gas panel according to claim 1, wherein one of said gascomponents comprises a pressure transducer.
 5. A gas panel according toclaim 1, wherein said valve comprises a pneumatic valve.
 6. A gas panelaccording to claim 1, wherein said valve comprises a manual valve.
 7. Agas panel according to claim 1, wherein one of said gas componentscomprises a pressure regulator.
 8. A gas panel comprising:a plurality ofone-piece manifold bodies, each of said manifold bodies having thereonat least three identical component receiving stations, each of saidcomponent receiving stations having a gas inlet and a gas outlet, thegas outlet from a first component receiving station of the pluralitybeing connected by a permanent connection with the manifold to a gasinlet to a neighboring component receiving station; a gas shut-off valveconnected to one of the receiving stations on one of the manifoldblocks; and a mass flow controller connected to receive gas from the gasshut-off valve.
 9. A gas panel according to claim 8, further comprisinga purifier connected to one of said one-piece manifold bodies.
 10. A gaspanel according to claim 8, further comprising a filter connected to oneof said one-piece manifolds.
 11. A gas panel according to claim 8,further comprising a pressure transducer connected to one of saidone-piece manifolds.
 12. A gas panel according to claim 8, furthercomprising a pressure regulator connected to one of said one-piecemanifolds.
 13. A gas panel comprising:a plurality of gas inlets; aone-piece gas panel manifold connected to each inlet of each of saidplurality of said gas inlets, each of said one-piece gas panel manifoldsdefining a substantially transverse gas path therethrough and having aplurality of active device stations positioned across a top facethereof, the substantially transverse gas path comprising a plurality ofV-channel gas passageways terminating at the active device stations; aplurality of removable active devices removably connected to each of theactive device stations for receiving said gas, the removable activedevices providing gas communication between selected ones of theV-channel passageways, each of said removable active devices beingconnected by a single device connector to couple both to inlet andoutlet ports of the active device station; and a plurality of gasoutlets connected to the one-piece manifolds.
 14. A gas panel accordingto claim 13, wherein said removable active devices further comprise: ashutoff valve, a pressure regulator and a mass flow controller.
 15. Agas panel according to claim 14, wherein said removable active devicesfurther comprise a manual shut-off valve.
 16. A gas panel according toclaim 13, wherein an interface region between the manifold and theactive devices is substantially planar and substantially parallel to theflow of gas from the inlet of the manifold to the outlet of themanifold.